<html>
 <head>
  <link href="./leetcode-problem.css" rel="stylesheet" type="text/css">
 </head>
 <body>
  <div class="question_difficulty">
   难度：Medium
  </div>
  <div>
   <h1 class="question_title">
    3. Longest Substring Without Repeating Characters
   </h1>
   <p>
    Given a string, find the length of the
    <b>
     longest substring
    </b>
    without repeating characters.
   </p>
   <div>
    <p>
     <strong>
      Example 1:
     </strong>
    </p>
    <pre>
<strong>Input: </strong><span id="example-input-1-1">"abcabcbb"</span>
<strong>Output: </strong><span id="example-output-1">3 
<strong>Explanation:</strong></span> The answer is <code>"abc"</code>, with the length of 3. 
</pre>
    <div>
     <p>
      <strong>
       Example 2:
      </strong>
     </p>
     <pre>
<strong>Input: </strong><span id="example-input-2-1">"bbbbb"</span>
<strong>Output: </strong><span id="example-output-2">1
</span><span id="example-output-1"><strong>Explanation: </strong>T</span>he answer is <code>"b"</code>, with the length of 1.
</pre>
     <div>
      <p>
       <strong>
        Example 3:
       </strong>
      </p>
      <pre>
<strong>Input: </strong><span id="example-input-3-1">"pwwkew"</span>
<strong>Output: </strong><span id="example-output-3">3
</span><span id="example-output-1"><strong>Explanation: </strong></span>The answer is <code>"wke"</code>, with the length of 3. 
             Note that the answer must be a <b>substring</b>, <code>"pwke"</code> is a <i>subsequence</i> and not a substring.
</pre>
     </div>
    </div>
   </div>
  </div>
  <div>
   <h1 class="question_title">
    3. 无重复字符的最长子串
   </h1>
   <p>
    给定一个字符串，请你找出其中不含有重复字符的&nbsp;
    <strong>
     最长子串&nbsp;
    </strong>
    的长度。
   </p>
   <p>
    <strong>
     示例&nbsp;1:
    </strong>
   </p>
   <pre><strong>输入: </strong>"abcabcbb"
<strong>输出: </strong>3 
<strong>解释:</strong> 因为无重复字符的最长子串是 <code>"abc"，所以其</code>长度为 3。
</pre>
   <p>
    <strong>
     示例 2:
    </strong>
   </p>
   <pre><strong>输入: </strong>"bbbbb"
<strong>输出: </strong>1
<strong>解释: </strong>因为无重复字符的最长子串是 <code>"b"</code>，所以其长度为 1。
</pre>
   <p>
    <strong>
     示例 3:
    </strong>
   </p>
   <pre><strong>输入: </strong>"pwwkew"
<strong>输出: </strong>3
<strong>解释: </strong>因为无重复字符的最长子串是&nbsp;<code>"wke"</code>，所以其长度为 3。
&nbsp;    请注意，你的答案必须是 <strong>子串 </strong>的长度，<code>"pwke"</code>&nbsp;是一个<em>子序列，</em>不是子串。
</pre>
  </div>
 </body>
</html>